From: Vijay Anusuri <vanus...@mvista.com> Upstream-Status: Backport from https://gitlab.com/qemu-project/qemu/-/commit/405484b29f6548c7b86549b0f961b906337aa68a
Reference: https://security-tracker.debian.org/tracker/CVE-2023-6683 Signed-off-by: Vijay Anusuri <vanus...@mvista.com> Signed-off-by: Steve Sakoman <st...@sakoman.com> --- meta/recipes-devtools/qemu/qemu.inc | 1 + .../qemu/qemu/CVE-2023-6683.patch | 92 +++++++++++++++++++ 2 files changed, 93 insertions(+) create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2023-6683.patch diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc index ad6b310137..4747310ae4 100644 --- a/meta/recipes-devtools/qemu/qemu.inc +++ b/meta/recipes-devtools/qemu/qemu.inc @@ -108,6 +108,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \ file://scsi-disk-allow-MODE-SELECT-block-desriptor-to-set-the-block-size.patch \ file://scsi-disk-ensure-block-size-is-non-zero-and-changes-limited-to-bits-8-15.patch \ file://CVE-2023-42467.patch \ + file://CVE-2023-6683.patch \ " UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar" diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2023-6683.patch b/meta/recipes-devtools/qemu/qemu/CVE-2023-6683.patch new file mode 100644 index 0000000000..e528574076 --- /dev/null +++ b/meta/recipes-devtools/qemu/qemu/CVE-2023-6683.patch @@ -0,0 +1,92 @@ +From 405484b29f6548c7b86549b0f961b906337aa68a Mon Sep 17 00:00:00 2001 +From: Fiona Ebner <f.eb...@proxmox.com> +Date: Wed, 24 Jan 2024 11:57:48 +0100 +Subject: [PATCH] ui/clipboard: mark type as not available when there is no + data +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +With VNC, a client can send a non-extended VNC_MSG_CLIENT_CUT_TEXT +message with len=0. In qemu_clipboard_set_data(), the clipboard info +will be updated setting data to NULL (because g_memdup(data, size) +returns NULL when size is 0). If the client does not set the +VNC_ENCODING_CLIPBOARD_EXT feature when setting up the encodings, then +the 'request' callback for the clipboard peer is not initialized. +Later, because data is NULL, qemu_clipboard_request() can be reached +via vdagent_chr_write() and vdagent_clipboard_recv_request() and +there, the clipboard owner's 'request' callback will be attempted to +be called, but that is a NULL pointer. + +In particular, this can happen when using the KRDC (22.12.3) VNC +client. + +Another scenario leading to the same issue is with two clients (say +noVNC and KRDC): + +The noVNC client sets the extension VNC_FEATURE_CLIPBOARD_EXT and +initializes its cbpeer. + +The KRDC client does not, but triggers a vnc_client_cut_text() (note +it's not the _ext variant)). There, a new clipboard info with it as +the 'owner' is created and via qemu_clipboard_set_data() is called, +which in turn calls qemu_clipboard_update() with that info. + +In qemu_clipboard_update(), the notifier for the noVNC client will be +called, i.e. vnc_clipboard_notify() and also set vs->cbinfo for the +noVNC client. The 'owner' in that clipboard info is the clipboard peer +for the KRDC client, which did not initialize the 'request' function. +That sounds correct to me, it is the owner of that clipboard info. + +Then when noVNC sends a VNC_MSG_CLIENT_CUT_TEXT message (it did set +the VNC_FEATURE_CLIPBOARD_EXT feature correctly, so a check for it +passes), that clipboard info is passed to qemu_clipboard_request() and +the original segfault still happens. + +Fix the issue by handling updates with size 0 differently. In +particular, mark in the clipboard info that the type is not available. + +While at it, switch to g_memdup2(), because g_memdup() is deprecated. + +Cc: qemu-sta...@nongnu.org +Fixes: CVE-2023-6683 +Reported-by: Markus Frank <m.fr...@proxmox.com> +Suggested-by: Marc-André Lureau <marcandre.lur...@redhat.com> +Signed-off-by: Fiona Ebner <f.eb...@proxmox.com> +Reviewed-by: Marc-André Lureau <marcandre.lur...@redhat.com> +Tested-by: Markus Frank <m.fr...@proxmox.com> +Message-ID: <20240124105749.204610-1-f.eb...@proxmox.com> + +Upstream-Status: Backport [https://gitlab.com/qemu-project/qemu/-/commit/405484b29f6548c7b86549b0f961b906337aa68a] +CVE: CVE-2023-6683 +Signed-off-by: Vijay Anusuri <vanus...@mvista.com> +--- + ui/clipboard.c | 12 +++++++++--- + 1 file changed, 9 insertions(+), 3 deletions(-) + +diff --git a/ui/clipboard.c b/ui/clipboard.c +index 3d14bffaf80..b3f6fa3c9e1 100644 +--- a/ui/clipboard.c ++++ b/ui/clipboard.c +@@ -163,9 +163,15 @@ void qemu_clipboard_set_data(QemuClipboardPeer *peer, + } + + g_free(info->types[type].data); +- info->types[type].data = g_memdup(data, size); +- info->types[type].size = size; +- info->types[type].available = true; ++ if (size) { ++ info->types[type].data = g_memdup2(data, size); ++ info->types[type].size = size; ++ info->types[type].available = true; ++ } else { ++ info->types[type].data = NULL; ++ info->types[type].size = 0; ++ info->types[type].available = false; ++ } + + if (update) { + qemu_clipboard_update(info); +-- +GitLab + -- 2.34.1
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